It is widely known that paper shredders for shredding incorporate plural cutting blades and spacers passing through rotary shafts that are driven to rotate towards each other by a motor and gear box so as to shred paper passing through the rotary shafts into strips by shear forces.
The maximum sheet capacity of the conventional paper shredders is dependent on the motor load and the limitations of the cutting blades and rotary shafts. Thus, when a large amount of paper is to be destroyed, the user must continuously feed the paper that is within the maximum sheet capacity of the paper shredded into the paper shredder manually in order to destroy the entire batch of documents.
Paper shredders may provide a peripheral auto-feed that would allow automatic feeding of multiple pieces of paper into paper shredder for shredding, such as that disclosed in TW414725 disclosing a paper feeder capable of automatically feeding documents or piles of paper into a shredder for shredding. The paper includes a pivotal driving roller assembly and a swingable top support. The pivotal driving roller assembly includes a driving roller and a pivotal roller for providing a driving force below a pile of paper, thereby separating a small pile of paper from the entire pile, and advancing the small pile of paper into a paper shredder located at downstream for shredding. U.S. Pat. No. 5,362,002 discloses a paper shredder with automatic paper feeding device The feeding device includes a tray which is mounted to the casing adjacent to the shredding roller assembly, a rotary shaft which is mounted rotatably on the tray, a tension spring which is connected to the rotary shaft and the tray, and at least one push rod, each of which having two pivotally connected rod sections. A first one of the rod sections is mounted on the rotary shaft, while a second one of the rod sections is provided with a press piece which presses against a stack of paper sheets on the tray. The feeding device further includes a pinion which is mounted securely on one end of the rotary shaft, and a wheel which has a sector portion formed with gear teeth and which is driven rotatably by the motor driving unit so as to drive rotatably and intermittently the pinion to rotate correspondingly the rotary shaft against action of the tension spring to cause movement of the press piece and some of the paper sheets toward the shredding roller assembly. Further, the co-owned U.S. Pat. No. 5,884,855 discloses a paper feed structure for paper shredders having a paper bearing device and paper feed adjustment device. The paper feed structure includes oblique paper bearing plate disposed above wheel cutters of the paper shredder, a paper feed adjustment device, an infrared shielded switch having the function of actuating the paper shredder, a paper feed roller, and slidable plates. Paper need not be fed one by one into the paper shredder manually, and the paper feed amount is adjustable. A pile of paper can be placed on the paper bearing device and the paper is automatically fed into the paper shredder one by one.
The paper feeders and paper shredders described above are in fact independent devices. That is, the paper shredders are peripheral devices that are added to the paper shredders and adopt structure that is similar to the paper feeding tray adopted by the conventional printers. Thus, upon placing a pile of paper in a paper tray, the paper feeder will utilize gear boxes, rods or conveyors to advance the leading edge of the bottommost paper into an inlet of the paper shredder. In other words, such paper feeders require the use of additional motor driving units. and driving components and thus involve higher manufacturing cost. In addition, they require space that is beyond that occupied by the paper shredder casing, such that they lack a unified appearance while failing to fulfill their maximum efficacy within minimum space.
Thus, it is essential to provide an auto-feed that is built-in a paper shredder casing so as to reduce the space as occupied by the paper shredder and paper feeder.